When tabbing between form fields, when you land on a checkbox or a radio button there is no indication that the focus is on that item. In plain HTML forms with no CSS the checkboxes and radio buttons "glow" yellow. In other browsers (IE7, IE8, FF3) there is a dotted outline indicating the item that is focused.

Checkboxes and radio buttons should have a visual indication that they have tab focus.

The result that occurs instead:

Nothing

Debugging already done:

Looked at CSS rules applied to these elements when focused, didn't see anything relating to :focus
Added a rule to apply (outline: 1px dotted;) to all checkboxes and radio buttons. This shows the outline when not focused and the outline disappears when focused.
Added a :focus rule with same same rule as above, nothing happened when focused.